Clinton deleted about 30,000 emails from the private server setup she used while serving as secretary of State, saying they were not work-related, before turning over thousands more to the government. But while examining her machines, the FBI recovered some additional emails that could be relevant to the FOIA lawsuit.

A preliminary review of the 15,000 emails revealed that about 60 percent were of a purely personal nature. Around 37 percent — or 5,600 documents — were deemed work-related, but of those, a “substantial number” were exact duplicates of the 30,000 emails that Clinton turned over to the agency in December 2014, according to State Department lawyers.